That the vibration is caused by the A6 getting to the final gear way to soon!!!! Thats what I am gathering!

Well, it could be that just the change in RPM is making the vibration change it's harmonics which in turn makes the vibration go away. To me it doesn't really prove that the cause of the vibration is from being in 6th gear too soon.

Basically what he is saying is that the PCM is making the transmission shift to 6th gear at lower rpms than it should. However, I don't think it is this simple. The manual transmission cars have the same problem. I can make mine do it at 2000 to 2200 rpms steady speed 30 to 35 mph in third gear. If I UP shift at that speed to 4th it drops rpms to 1700 or so and the vibtration goes away. I firmly believe this is a throttle position, MAP, timing and VVT tune issue. When you shift, either up or down, you force the engine to a different point on the tune table and thus it stops vibrating like my old Harley. Since both manuals and autos are having this problem, it isn't a torque converter shake issue either. The only other thing which could be causing it is exhaust reversion which would cause the AFR to jump all over the place when exhaust gases are reverting back up through exhaust valves, then intake valves and thus messing up in incoming intake charge. This is why I asked in antoher thread on this if anyone with long tube header (would change reversion timing or eliminate it) or anyone with a Trifecta tune is having the issue.

My Camaro V6 Automatic also vibrates while driving at 37 - 47 mph at 1100 rpms. The automatic is set to shift to 6th gear once you hit a certain speed. For me I think its around 37 MPH. If I lift my foot or if I accelerate the vibration goes away temporarly. Now if you put the car in "M" (Manual Mode) then depress one of the shifter buttons on the steering wheel to have the car enter paddle shift. You can avoid the vibration all togather because who in the correct mind would be in 6th gear while driving at 37 mph. I really think Chevrolet should do something about that shift point. Perhaps keep it in 5th gear until say 50 mph or X rpm.